Method of recovering iron and steel from slags.



PATENTED OCT. 9, 1906..

R. BAGGALEY. METHOD OF REGOVERING IRON AND STEEL FROM SLAGS.

APPLICATION FILED PEB.8. 1906.

INVENTOR f 4 mdm rzziz No. 832,948." PATBNTED OCT. 9, 1906.

R. BAGGALEY. METHOD OF RECOVERING IRON AND STEEL FROM SLAGS.

APPLICATION FILED FEB. 8, 1906.

2 SHEETS-SHEET 2.

WITNESSES INVENTOR 11 concern; y RALPH Bassinet, of

g, zlQll'egneiiy county, Pennsylvania, vented a new and Method of o firing Iron and Steel from Ferruginous which the following is a full, clear,

and exact description, reference being had to the accorm anying drawings, in Which- "l iifiure 1 is a vertical central section rough a furnace suitable tor the practice of myinvention; and Fig. 2 is an elevation, on

' a larger scalc,-of the letter part of the furnace. present invention cr'ng iloys, in lieu of 'carefully selocted. oxulrzed-non ores as it source of iron, icrruginous slags that result" "from tlm'sqaaration of copper, gold, and s'il or from their ores, and which ores notoriously contain large proportions cl impur ties This mate- Whcrcvcr copper is 1 reduced however, to my knowledge" any instance this invention. p p sunply as a.,'-waste'byproduct and an ex tremcly expensive one to dispose of at all where this material is now used or Where it ever has been used as ;a source from which to produce iron or steel, as contemplated by It IS universally"regarded coppenproducing plants. Tlhe di'lliculties oi recovering the iron by reason oi" association with its many objectionable impurities are very great, and thus far they have battled the most expert metallurgists. Yet the fact remains that pig-iron and steel arc invariably expensive and scarce Wherever copper-smelters are operated. Hence the recovery of such iron from such Waste material for use in the arts is important. It will be apparent that in using this wasteby-product as the source of an iron-supply I may be able to do things and to sacrifice proportlons of such iron in my various treatment processes v necessary in expelling the objectionable impurities that would not be commerciall possible Where high-priced oxidized and se ected ores are depended upon as the original source of the iron-supply.

I am aware that the cinder resulting from the subliming of n'on-cupriferous ores used by the manufacturers of sulfur and sulfurous, sulfuric, and anhydrous acids has been, or at all events is, ca able of being used in the manufacture of cast-iron and Bessemer steel; but the ability to use this cinder for the in or PHTSBH 0F[Reconnaissance' ass sm z'ss m s a Specification of y 7 Application aria-my 8,1908. s rains. 300,073. 1

orrion isnsrnihin Al.

L inma es.emot con pur ose stated in so far as Bessemer steel is" concerned, is due solely to twofs'cts: first, because copper is not present oris present in minute proportions second, because of the fact thatis'uch ores by some"strangefre ak of nature are always devoid of phosphorus.

Sulfur and sulfurous, sulfuric ,and anhydrbus acids, may also be produced fromores that contain copper, andin thiscase the result-ant cindcrs are often subsequently treated for the recovery of the copper; but, so far as I know, they have not been made toyie ld up their contained 11011 111 such form as to ma ke it valuable {or use In the arts.

The object of invention isto save the" ron contained in the terruglnous slag ofco'p pensmelting furnaces, that has heretofore been Wasted,'by utilizing suchslag as a substitute for iron ores; and to that-end my' -in'ven tion consists in first smelting such ferru g'inous slags in combination with carbonaceous incl in a suitable lurnace, employing for the purpose of separating ,thejcontained iron such fiuxing agent, preferably l1mestone,,as

maybe essential.

v I use such intense heats as maybe necessary to accomplish theseparationof the silica, and

thereby Iainen'abled to replace the silica with the silicate of lime, which thereafter readily separates from the iron. The heat Which is employed in the furnace is much higher than that which employed in the ordinary blast-furnacesfcr smelting iron ores, since I h e discovered that in order successfully to obtain the iron from copper-smelter slag-g and to separate it from the impurities therein I must employ not only a large percentag' oi fluxing material, but a much higher heat than must be employed'in the smelting of iron ores. I believe that in this way I an the first to provide for the successful and economical smelting of a hitherto waste prodnot. The furnace which I employ is adapted to Withstand such high heat, and for that purpose its lower portion-is either formed of I water-cooled. sections or of other material which can Withstand the high temperature jackets in which the flow of the cooling agent is'regulated at will, and I also haveavailable an auxiliary heat capable of any desired intensity and capable of instant regulation. I can also aid the process by means of the converting-blast, though other smelting or melting furnaces may be employed.

The ferruginous slag discharged from copper-smelting furnaces is composed of silica combined with iron and other'bases, which fact will demand the use of fluxing' agents. The silica can be separated from thecontained iron b means of limestone as a fluxin agent. it will be apparent to those skilled in the art that the lime of the limestone and the silica Will combine as a slag, and thereafter in the operation of bessemerizing the. various impurities are eliminated in succession in the order of their' oxidation. The last vestiges the sulfur in their elimination will demand the Sacrifice of a. considerable percentage of the-iron, which in this process is permissible, while in ordinary iron and steel making it is not permissible, for commercial reasons. In some cases also it will demand the almost total elimination of the carbon, and in such cases the carbon must be restored to the bath by means of the addition of suitable percentages of spiegeleisen or ferromanganese as carbon-bearing agents. The

roduct of this smelting operation is castiron combinedwith various impurities, according to the analysis of the ores used, and

a to convert it into steel I bessermeize it, either by tapping it from the smelting-furnace and transferring it to a converter or by providing thesmelting-furnace with a 'bessemerizingchamber having twyers through which air eanbe blown into the molten iron. The decarburized iron. thus produced is recarburized with spiegeleisen or other suitable additions and ma then be cast into ingots, if forgin'gs are desired, or into other desired forms, if castings are wanted.

I am enabled by my invention to obtain a useful product, either pig-iron or steel, from the ferruginous slag, which hitherto has been treated as a waste material, and in this way I effect a large ecnomy.-

In the drawin s, 2 represents a smeltingfurnace suitable for the practice of my inven tion, having a charge-opening 3, twyers 4. 4, a hearth 5, a metal tap-hole 6, a slag-tap 7, and Water-jacket 8. The hearth 5 is preferably movable, being mounted upon wheels 9, so that it can be removed and relined When necessary. I

I claim- 1. The method herein described of obtaining iron from the ferruginous slag of a copper-furnace, which consists in smelting such slag with carbonaceous fuel and flux and subjecting it to a temperature higher than that ordinarily employed in an iron blast-furnace substantially as described. I

2. The method herein described of obtaining iron from the ferruginous slag of a copper furnace, which consists in smelting such slag with carbonaceous fuel and flux, subjecting it to a temperature higher than that ordinarily employed in an iron blast-furnace, and bessemerizing the iron which is produced substantially as described.

In testimony whereof I have hereunto set my hand.

' RALPH BAGGALE Witnesses:

WILLIAM M. KIRKPATRICK, FRANK L. RILEY. 

